When trekking into hostile territory most went in "brigades" as the mountain men did. Made sense also as there are more threats in the frontier than just hostiles.
Rifles have been documented to be popular with the "longhunters" who hunted for a living. But I think we have a modern misconception about how they were used. First there is the issue of the smaller calibers whcih make a lot of sense. But couple them also with lighter charges than we use today. If I were to ask about hunting with a 45 most would recommend about 60-70 grains of BP for deer. Yet recommendations still exist to load a rifle till one hears a "crack" and older measures were also at smaller capacity. The crack is easily achieved in a 45 at about 40 grains. A 120 grain bullet launched at a little over 1100 fps might surprise the modern hunter in its effectiveness. At about the turn of the 20 century, calibers like the 32-20 were developed which were commonly called "trappers rifles" These were said to be good for both large and smaller game and were used as such. A 40 ML will about duplicate a 32-20 when loaded lighter and theere seemd to exist more than a few calibers between 40-45 as ML calibers were not really all that standardized. JF Cooper wrote about loading rifles light in his Pathfinder series. Careful shooting permits the use of smaller calibers and allows one to carry more shots per weight.
DP